SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8f24e1aedf943b123545daed3826227563bd01d91a4eedd1bd8556102782032c' 
  AND token = '2AQ3Quyteh0qcN2hLfAE/BuvgLxCj4VtfNLwMn8PMv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}